Probe the new mdio node added by 
b31a1d8b.  Fix kernel panic problem when
gianfar driver wants to get the of_platform_device of that mdio.
Signed-off-by: Li Yang <leoli@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
 
                        cell-index = <0>;
                        device_type = "network";
                        model = "eTSEC";
-                       compatible = "gianfar", "simple-bus";
+                       compatible = "gianfar";
                        reg = <0x24000 0x1000>;
                        local-mac-address = [ 00 00 00 00 00 00 ];
                        interrupts = <37 0x8 36 0x8 35 0x8>;
 
 
 static struct of_device_id __initdata of_bus_ids[] = {
        { .compatible = "simple-bus" },
+       { .compatible = "gianfar" },
        {},
 };